Formwork Restraint

ABSTRACT

In one arrangement, shown in FIG. 1, there is provided a formwork restraint for a reinforcement bar. The formwork restraint includes a restraint portion for receiving the reinforcement bar. The formwork restraint further includes a support portion adapted to connect the restraint portion to a reinforcing formwork arrangement to maintain a desirable relationship between the reinforcement bar and the reinforcing formwork arrangement.

FIELD

In one preferred arrangement, the present invention relates to aformwork restraint.

BACKGROUND TO THE INVENTION

In the construction of buildings a concrete slab may be provided with anumber of starter bars extending a suitable distance upwardly away fromthe concrete slab. The starter bars typically provide both a referencepoint and reinforcing for a further section built upwardly from theconcrete slab.

When preparing a concrete slab, starter bars are typically either fixedin position with the use of wire ties before the concrete is poured.With wire, the process of wire tying involves positioning each starterbar and twisting and cutting the wire to form numerous ties to hold thestarter bars in position. This process is particularly labour intensiveand time consuming.

Other system of fixing starter bars include: (i) continuity systemswhere pre-bent bars are positioned to extend through a number of holesin a casing; and (ii) anchor systems where ends of the starter bars arepushed into anchors. These systems tend only to be suitable forparticular situations and can be complex and costly.

It is against this background and the problems and difficultiesassociated therewith that the present invention has been developed.

SUMMARY OF THE INVENTION

According to a first aspect of preferred embodiments herein describedthere is provided a formwork restraint for a reinforcement barcomprising:

a restraint portion for receiving the reinforcement bar; and

a support portion adapted to connect the restraint portion to areinforcing formwork arrangement to maintain a desirable relationshipbetween the reinforcement bar and the reinforcing formwork arrangementwhen the reinforcement bar is received by the restraint.

Preferably the support portion comprises a spacer for spacing therestraint portion at least a predetermined distance laterally away fromthe reinforcing formwork arrangement. The reinforcement bar may comprisea starter bar and the reinforcing formwork arrangement may comprises atrench mesh.

In one preferred arrangement the support portion comprises threeelongate arms each having a clip for clipping the corresponding arm to abar of the reinforcing formwork arrangement. In another preferredarrangement the support portion comprises a securing portion having afirst slot adapted to receive and hold at least two substantiallyparallel bars of the reinforcing formwork arrangement.

Particularly preferred arrangements of the present invention provide anadvantageously convenient and labour saving alternative to having towire tie each starter bar to a trench mesh in a formwork arrangement.Having to provide numerous wire ties in such a system is often labourintensive or otherwise problematic.

According to a second aspect of the preferred embodiments hereindescribed there is provided a formwork system for maintaining theposition of a plurality of starter bars relative to a reinforcing meshstructure, the system comprising:

a plurality of starter bar holders each having a first portion forreceiving a respective starter bar and a second portion extendingtherefrom for connecting the respective starter bar to the reinforcingmesh structure;

wherein the first portions and the second portions of the starter barholders are adapted to maintain the starter bars and reinforcing meshstructure in a desirable relative position.

Preferably the formwork system includes spacer elements for spacing baseportions of the starter bars above the ground such that in use the baseportions of the starter bar holders restrain movement of the starterbars relative to the reinforcing mesh structure at positions spaced awayfrom the reinforcing mesh structure

According to a third aspect of preferred embodiments herein describedthere is provided a formwork holder comprising:

a first portion for receiving an elongate formwork element; and

a second portion extending from the first portion for engaging a planarformwork arrangement to hold the elongate formwork element and planarformwork arrangement in relative position when the formwork element isreceived by the first portion.

According to a fourth aspect of preferred embodiments herein describedthere is provided a formwork restraint for a plurality of starter barscomprising: a body having a plurality of connection elements spacedtherealong; the connection elements each defining an opening forreceiving a corresponding starter bar.

According to a fifth aspect of preferred embodiments herein describedthere is provided a method of providing a reinforced concrete structure,the method comprising:

providing a plurality of starter bars; a reinforcing mesh structure anda plurality of formwork restraints; and

coupling first portions and second portions of the formwork restraintswith the starter bars and reinforcing mesh structure respectively;

wherein the first portions are positioned to restrain relative movementof the starter bars and the reinforcing mesh structure.

According to a sixth aspect of the preferred embodiments hereindescribed there is provided a support for a starter bar systemcomprising: a first member and a second member, with a third membertherebetween; wherein the first and second members are adapted tosupport a mesh above the ground and the third member is adapted tosupport a starter bar.

According to a seventh aspect of the preferred embodiments hereindescribed there is provided a formwork restraint adapted to bepositioned on a starter bar to engage horizontally extending formworkbars therebelow.

Preferred embodiments of the present invention are considered to providea number of advantageous systems and methods including:

A formwork restraint that holds a starter bar in a vertical positionduring a concrete pour;

A formwork restraint that allows a starter bar to be inserted through ahole in a holder and for lower clips to be clipped onto a trench mesh toprovide a relatively stable cradle during a concrete pour;

(iii) A formwork restraint that restrains a starter bar an advantageousdistance above a trench mesh and which then extends downwardly tosupport a number of parallel bars of the trench mesh in a single slot;

(iv) A formwork restraint that holds starter bars at relatively equalspacings during a concrete pour; and

(v) A formwork restraint system that allows for the ready placement andalignment of starter bars relative to a trench mesh where each starterbar is relatively positioned at three locations.

It is to be recognised that other preferred forms and preferredadvantages of the present invention will be apparent from the drawingsand detailed description, along with the claims provided herebelow.

BRIEF DESCRIPTION OF DRAWINGS

In order to facilitate a better understanding of the present invention,several preferred embodiments of the present invention will now bedescribed with reference to the accompanying drawings, in which:

FIG. 1 is a perspective view of a formwork restraint according to afirst preferred embodiment of the present invention;

FIG. 2 is a perspective view of the formwork restraint shown in FIG. 1,with the formwork restraint fitted to a starter bar and a trench mesh;

FIG. 3 is a perspective view of a formwork system according to a secondpreferred embodiment of the present invention;

FIG. 4 is a top view of a formwork restraint according to a thirdpreferred embodiment of the present invention, the formwork restraint ofFIG. 4 also being shown in FIG. 3;

FIG. 5 is a side view of a formwork restraint according to a fourthpreferred embodiment of the present invention;

FIG. 6 is a fop view of the formwork restraint shown in FIG. 5; and

FIG. 7 is an illustrative view of a method according to a fifthpreferred embodiment of the present invention;

FIG. 8 is a perspective view of a formwork restraint according to afurther preferred embodiment; and

FIGS. 9 to 11 are engineering drawings showing possible measurements andrelatively sizings of several of the preferred embodiments.

DETAILED DESCRIPTION OF THE DRAWINGS

Referring to FIG. 1 there is illustrated a formwork restraint 10according to a first preferred embodiment of the present invention. Theformwork restraint 10 is further illustrated in FIG. 2 as advantageouslymaintaining a desirable relationship between a reinforcement bar 12 anda reinforcing formwork arrangement 14. In the embodiment, thereinforcement bar 12 is provided as a starter bar 16 and the reinforcingformwork arrangement 14 is provided as a trench mesh 18.

The formwork restraint 10 includes a restraint portion 20 for receivingthe starter bar 16. The restraint portion 20 comprises a body 24 havinga top portion 26 and a lower portion 28. The top portion 26 is reducedin diameter in comparison to the lower portion 28. The top portion 26has an outer diameter of 40 mm and an inner diameter of 12 mm. The innerdiameter of 12 mm is defined by a passage 27 that extends through thebody 24. The passage 27 is adapted to receive the starter bar 16 whichhas a diameter of about 11 mm. In order to accommodate starter bars of adifferent diameter a narrower passage 27 may be used. Other forms ofrestraint portion 20 are envisaged.

The formwork restraint 10 includes a support portion 36 that is adaptedto connect the restraint portion 20 to the mesh 18, as shown in FIG. 2.The mesh 18, in this embodiment, is provided as a series of overlayedreinforcement bars 38 that are welded together and supported on spacers(not shown) disposed on the ground. The mesh 18 is provided as anintegral welded mesh that is manufactured as a sheet.

The support portion 36 of the formwork restraint 10 comprises three arms40 including a first arm 42, a second arm 44 and a third arm 46. Each ofthe three arms 40 is formed from flexible plastics material. Therestraint portion 20 and support portion 36 are formed in one piece andare able to advantageously withstand the pressure of a concrete pour.

Each of the arms 42, 44, 46 includes a releasable connector 48 forconnecting each of the corresponding arms to the mesh 18. Eachreleasable connector 48 is provided in the form of a clip 50 having aninternal diameter of 11 mm to firmly engage and connect with the bars ofthe mesh 18. As indicated above, the restraint portion 20, and the arms42, 44, 46 (including the releasable connectors 48) are integrallyformed in one piece. This advantageously assists with ensuring that theformwork restraint 10 is able to withstand the pressure of a concretepour, when connected to the starter bar 16 and mesh 18.

In this embodiment, each of the arms 42, 44, 46 are of the same fixedlength and connect to the mesh structure 18 at similarly spacedlocations 56, 58, 62. Other embodiments may have arms of differentlength and be suited to different circumstances. As shown in FIG. 2, thearm 42 engages a first bar 64, the arm 44 engages a second bar 66 andthe arm 46 engages an intermediate bar 68 therebetween.

In operation a person constructing the formwork connects the clips 50 tothe bars 64, 66, 68. The length of the three arms 40 ensures that theyare suitably positioned. The three arms 40, by their resilient nature,ensure that support portion 36 provides a spacer that serves to spacethe restraint portion 20 at least a predetermined distance 69 laterallyaway from reinforcing mesh structure 18. It is presently preferred thatthe length of each of the arms 42, 44 and 46 is between about 250 mm and400 mm and that the distance 69 is between 350 mm and 400 mm. In thepresent embodiment the length of the arms 42, 44 and 46 is about 330 mm.Other lengths are of course possible.

By spacing the the restraint portion 20 away from the mesh structure 18,using the arms 40, the formwork restraint 10 is able to advantageouslymaintain the alignment of the reinforcement bar 12 during a concretepour. The three elongate arms 42, 44 and 46 and the restraint portion 20accordingly maintain a desirable relationship between the starter bar 16and the mesh 18, when the starter bar 16 is received in the restraintportion 20 as shown in FIG. 2. In this embodiment the lower bend 67 ofstarter bar 16 is supported by a trench chair (not shown).

When laying a foundation in a trench, the use of a number of formworkrestraints 10 is considered to be particularly advantageous to improvethe formwork alignment and provide significant labour savings. This isespecially the case in comparison to conventional techniques includingthose using thin wire to tie the starter bar 16 to the mesh 18 to holdthe mesh 18 in position above the ground. Depending upon thecircumstances, with the use of a number of formwork restraints 10, itmay be possible to support the mesh 18 from the starter bar 16, withouthaving to use spacers to directly support the mesh 18 from the ground.

Referring to FIG. 3 there is shown a formwork system 70 according to asecond preferred embodiment of the present invention. The formworksystem 70 advantageously maintains the position of a plurality ofstarter bars 72 relative to a reinforcing mesh structure 74. Theformwork system 70 is used to provide a reinforced concrete foundationin an elongate trench 76.

The system includes starter bar holders 78 each having a first portion82 for receiving a corresponding one of the starter bars 72 and a secondportion 84 that extends therefrom for connecting the correspondingstarter bar 72 to the reinforcing mesh structure 74. The first portions82 and the second portions 84 of the starter bar holders 78 are adaptedto maintain the starter bars 72 and the reinforcing mesh structure 74 ina desirable aligned relationship as shown in FIG. 3.

The starter bars 72 are provided as right angled starter bars havinghorizontally extending base portions 86. In the formwork system 70, thebase portions 86 of the starter bars 72 are supported by spacers (notshown) that are positioned on the ground on the bottom of the trench 76.Relative to the mesh structure 74, the starter bars 72 are restrained bythe spacers (not shown) and the first portions 82 of the starter barholders 78. The first portions 82 restrain the starter bars 72 atpositions spaced away from the mesh structure 74.

The formwork system 70 includes at least one formwork restraint 94. Theformwork restraint 94 forms a further preferred embodiment of thepresent invention and is further illustrated in FIG. 4. The formworkrestraint 94 is advantageously adapted to hold four starter bars asshown in FIG. 3. The formwork restraint 94 comprises an elongate body 96having four connection elements 98 spaced at regular intervals along theelongate body 96. The connection elements 98 each define an opening 100that is adapted for receiving a starter bar. In the formwork system 70the formwork restraint 94 is used to assist with maintaining the spacingof the starter bars 72 at regular intervals of about 400 mm. Thearrangement of FIG. 4 is considered to be advantageous.

Referring to FIG. 5 there is shown a formwork restraint 110 according toa fourth preferred embodiment of the present invention. The formworkrestraint 110 advantageously supports a right angled starter bar 112.

In the embodiment, there is provided a restraint portion 114 and asupport portion 116. As shown in FIG. 6, the restraint portion 114defines a passage 118 for receiving the starter bar 112. The walls ofthe passage 118 allow for the restraint portion 114 to be movedlaterally over starter bar 112, as opposed to having to be threadedtherealong. This is considered to be advantageous.

The support portion 116 is advantageously adapted to connect therestraint portion 114 and the starter bar 112 to a formwork structure120 to maintain alignment between the starter bar 112 and the formworkstructure 120.

As shown in FIG. 6, the support portion 116 comprises a first securingportion 122 and second securing portion 124. The securing portions 122,124 both include an extending portion 126 and an elongate U shaped slot128. Each extending portion 126 extends outwardly and downwardly awayfrom the restraint portion 114 and bends to extend into eachcorresponding U shaped slot portion 128. The form and arrangement of thefirst and second securing portions 122, 124 is shown in FIGS. 5 and 6.The first and second securing portions 122, 124 form a V shaped section130 (FIG. 6) and a C shaped section 132 (FIG. 5). Each U shaped slot 128includes a closed end 134 and an open end 136. Between the closed ends134 and the open ends 136 each U shaped slot 128 includes an upperelongate member 138 and a lower elongate member 140 which defines asecuring slot 142 therebetween.

Each of the first and second securing portions 122, 124 include an aclosure portion 144 at their corresponding open ends 136 on their lowerelongate members 140. The closure portions 144 are moveable between anopen and closed condition to allow three substantially parallel bars 146of the mesh structure 120 to be received in and extend between the twosecuring slots 140. Both slots 128 engage both sides of the bars 146.

The first and second securing portions 122, 124 operate to hold thethree bars 146 during a concrete pour. Movement of the bars 146 withinthe slots 120 is restrained by the closed end 134 and the closureportions 144. The closure portions 144 are biased towards a closedcondition by virtue of the lower elongate members 138 being made fromresilient plastics material.

FIGS. 5 and 6 also illustrate a support 150 according to a furtherpreferred embodiment of the present invention. The support 150 includesa first member 154 and a second member 156 connected by a third member158. The third member 158 is adapted to support the starter bar 112below the three bars 146 that extend over the starter bar 112. The threebars 146 are supported by the first member 184 and the second member 186with the third member 158 providing a holder 160 for the starter bar112. In this embodiment the holder 160 comprises a depression 162 shapedto receive the starter bar 112. The support 150 is considered to beadvantageous for the reasons that it can support a trench mesh andstarter bar at one location.

Referring to FIG. 7 there is shown a method 170 of providing areinforced concrete structure, according to another embodiment of thepresent invention. At block 172 the method comprises providing aplurality of starter bars 174, a mesh 176, a plurality of formworkrestraints 178 and a plurality of spacers 180. At block 182 the starterbars 174 are placed underneath the mesh 176 within a trench. This servesto hold the mesh 176 in place. Concrete is then poured into the trench.At block 184, once the required amount of concrete has been poured,another mesh layer is positioned and another layer of concrete ispoured. In the method 170, the starter bars 174 are fixed in positionusing the spacers 180 to hold the right angled base portions of starterbars 174 above the ground. The starter bars 174 are positioned relativeto the mesh 176 using the formwork restraints 178 and are regularlyspaced using further formwork restraints 186. Advantageously the starterbars 174 are fixed by being held at three locations. This is consideredto be beneficial in withstanding the pressure applied by the concrete asit is poured into the trench.

Referring to FIG. 8 there is shown a further embodiment in the form of aformwork restraint 200. The formwork restraint 200 includes a connector202 for attaching to formwork bars 204. The connector 202 includes afirst connector 206 provided as a pair of snap connectors 208 as well asa second connector 210 provided as a par of snap connectors 212. Thefirst connector 206 is arranged to snap onto a formwork bar 214. Thesecond connector 210 is arranged to snap onto a formwork bar 216. Asshown the releasable connector 202 is adapted to snap to the formworkbar 214 and the formwork bar 216 so as to span four formwork bars 204.This is considered to provide the formwork restraint 200 withadvantageous stability.

The formwork restraint 200 advantageously comprises a single unitarybody 218 formed from plastics material, where the body 218 is formed ina single mould. The releasable connector 202 is provided by a baseportion 220 for supporting an extension 222 for assisting withmaintaining an L-shaped starter bar 224 in an upright condition 226.

In this embodiment the extension 222 provides an upper portion 228through which the upright portion 232 of the starter bar 224 can extend.The upper portion 228 extends upwardly from the base portion 220 and isadvantageously configured to limit movement of the upright portion 232of the starter bard 224 to the extent of a channel 236 provided by theupper portion 228.

The base potion 220 advantageously provides a lower portion 238 throughwhich a horizontal portion 240 of the starter bar 224 can extend. Thelower portion 238 is advantageously configured to limit movement of theportion 240 to movement within a channel 242. The channels 236 and 242provide openings within the body 218 for restraining the starter bar224.

In order to fix the formwork restraint 220 in position, the formworkrestraint 220 is slid down the portion 232 of the starter bar 224 toengage the formwork bars 204 and receive and restrain the horizontalportion 240 of the starter bar 224.

FIGS. 9 to 11 provide engineering drawings showing measurements anddimensions and relative sizing of components of several of the preferredembodiments described above. Other embodiments, sizings and so forthare, of course possible.

It will be recognised that the embodiments described, as shown in theaccompanying drawings, provide a number of advantages including:

-   (i) The ability to maintain a desirable relationship between a    starter bar and a mesh in a formwork system where the starter bar is    restrained a predetermined distance away from the mesh.-   (ii) The ability to support both a starter bar and mesh in relative    position for a concrete pour in a trench mesh environment, where the    starter bars are spaced at regular intervals along the mesh.-   (iii) A method of readily positioning starter bars relative to a    mesh in a trench where the starter bars are restrained at a first    location with respect to the mesh, a further location above the    mesh, and a further location below the mesh.

It is to be recognised that various alterations and equivalent forms maybe provided without departing from the spirit and scope of the presentinvention. This includes modifications within the scope of the appendedclaims along with all modifications, alternative constructions andequivalents.

In the present specification, the presence of particular features doesnot preclude the existence of further features. The words “comprising”,“including” and “having” are to be construed in an inclusive rather thanan exclusive sense.

1. A formwork restraint for a reinforcement bar comprising: a restraintportion for receiving the reinforcement bar; and a support portionadapted to connect the restraint portion to a reinforcing formworkarrangement to maintain a desirable relationship between thereinforcement bar and the reinforcing formwork arrangement when thereinforcement bar is received by the restraint.
 2. A formwork restraintas claimed in claim 1 wherein the support portion comprises a spacer forspacing the restraint portion at least a predetermined distancelaterally away from the reinforcing formwork arrangement.
 3. A formworkrestraint as claimed in claim 2 wherein the support portion comprises areleasable connector for connecting the restraint portion to thereinforcing formwork arrangement.
 4. A formwork restraint as claimed inclaim 3 wherein the reinforcement bar comprises a starter bar and thereinforcing formwork arrangement comprises a substantially planar mesh.5. A formwork restraint as claimed 4 wherein the support portioncomprises three elongate arms each having a clip for clipping thecorresponding arm to a bar of the reinforcing formwork arrangement.
 6. Aformwork restraint as claimed in claim 4 wherein the support portioncomprises a securing portion having a first slot adapted to receive andhold at least two substantially parallel bars of the reinforcingformwork arrangement in the first slot.
 7. A formwork restraint asclaimed in claim 6 wherein the securing portion comprises a second slotspaced apart from the first slot such that the first and second slotsare both adapted for receiving and holding the at least twosubstantially parallel bars of the formwork arrangement either side ofthe reinforcement bar when the reinforcement bar is received by therestraint.
 8. A formwork restraint as claimed in claim 6 wherein thesecuring portion is biased toward maintaining the or each slot in aclosed condition for preventing movement of the at least twosubstantially parallel bars of the reinforcing formwork out of the slot.9. A formwork restraint as claimed in of claims 6 wherein the securingportion includes a closure that is moveable between a first conditionand a second condition, at an open end of the or each slot.
 10. Aformwork system for maintaining the position of a plurality of starterbars relative to a reinforcing mesh structure, the system comprising: aplurality of starter bar holders each having a first portion forreceiving a respective starter bar and a second portion extendingtherefrom for connecting the respective starter bar to the reinforcingmesh structure; wherein the first portions and the second portions ofthe starter bar holders are adapted to maintain the starter bars andreinforcing mesh structure in a desirable relative position.
 11. Aformwork system as claimed in claim 10 including spacer elements forspacing base portions of the starter bars from the ground such that inuse the base portions of the starter bar holders restrain movement ofthe starter bars relative to the reinforcing mesh structure at positionsspaced away from the reinforcing mesh structure.
 12. A formwork holdercomprising: a first portion for receiving an elongate formwork element;and a second portion extending from the first portion for engaging aplanar formwork arrangement to hold the elongate formwork element andplanar formwork arrangement in relative position when the formworkelement is received, by the first portion.
 13. A formwork restraint fora plurality of starter bars comprising: a body having a plurality ofconnection elements spaced therealong; the connection elements eachdefining an opening for receiving a corresponding starter bar.
 14. Aformwork restraint as claimed in claim 13 wherein the connectionelements are equally spaced along the body.
 15. A method of providing areinforced concrete structure, the method comprising: providing aplurality of starter bars; a reinforcing mesh structure and a pluralityof formwork restraints; and coupling first portions and second portionsof the formwork restraints with the starter bars and reinforcing meshstructure respectively; wherein the first portions are positioned torestrain relative movement of the starter bars and the reinforcing meshstructure.
 16. A method as claimed in claim 15 including: pouringconcrete over the reinforcing mesh structure; and curing the concrete toprovide a reinforced concrete structure with the starter bars extendingtherefrom.
 17. A method as claimed in claim 15 wherein coupling thefirst portions of the plurality of the formwork restraints comprisespassing ends of the starter bars through the first portions.
 18. Amethod as claimed in claim 16 or where coupling the second portions ofthe formwork restraints to the reinforcing mesh structure comprisesusing clips of the second portions to clip each second portion to thereinforcing mesh structure.
 19. A method as claimed in of claim 16wherein the reinforcing mesh structure comprises reinforcing mesh andthe method includes positioning bent portions of the starter barsunderneath the reinforcing mesh on spacers.
 20. A support for a starterbar system comprising: a first member and a second member, with a thirdmember therebetween; wherein the first and second members are adapted tosupport a mesh above the ground and the third member is adapted tosupport a starter bar.
 21. A support as claimed in claim 20 wherein thethird member is arranged to support the starter bar from below the mesh.22. (canceled)
 23. (canceled)
 24. (canceled)